1. Field of the Invention
The invention refers to a method for producing microspheres by means of vibration-stimulated dripping of liquid through a plurality of openings of a nozzle plate, the droplets taking on a spherical shape while falling through a first free-fall section and then, in a second free-fall section, being exposed to a reaction gas to produce gelling, thereafter falling into a reaction liquid which may possess a foam layer.
The invention further refers to an apparatus for producing microspheres, comprising a nozzle plate which has a plurality of openings for dripping a liquid and can be caused to vibrate; a reaction free-fall section in which the droplets falling from the nozzle plate react with a reaction gas; and a reaction liquid, present below the free-fall section in a vessel, which may be covered with a foam.
2. Description of the Prior Art
A corresponding method and apparatus are disclosed by DE 28 16 059 C3, referring to the production of a pelletized nuclear fuel; the resulting uranium oxide pellets have a diameter of approximately 80 um. It has been found in practice that larger spheres, in the range up to approximately 5 mm, cannot be produced with a corresponding method or apparatus, especially not in industrial-scale facilities.
Also known in addition to vibration-stimulated dripping is the gravity drip technique, although with this only small dripping rates of approximately 1 to 10 droplets per nozzle per second can be achieved.